Potentiometric device



y 8, 1951 T. J. WILSON 2,551,989

POTENTIOMETRIC DEVICE Filed Sept. 50, 1949 j I E. 2 aa av y' l4A 38 nnentor THEODORE J. WILSON (Ittorneg Patented May 8, 1951 POTENTIOMETRIC DEVICE Theodore J. Wilson, Minneapolis, Minn., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application September 30, 1949, Serial No. 118,788

10 Claims.

- l The present invention is concerned with a potentiometric device for use in electrical circuits. More particularly the present invention is concerned with providing an improved device which in a unitary assembly includes a plurality of potentiometer circuits with a wiper of each potentiometer being positioned by a common rotating element.

In the building of potentiometers, particularly those associated with the aircraft industry, it is necessary that these potentiometers be strongly constructed, be of minimum weight and occupy a minimum of space. When it is desired to provide a plurality of potentiometer circuits in a single device, it is even more essential that the device be kept as simple as possible to aid in the ease of fabrication and assembly of parts. This is accomplished in the present invention by compactly associating the various elements of the device so that the device will occupy a minimum of space with many of the elements performing dual functions in the construction and operation of the device.

It is therefore an object of the present invention to provide a new and improved potentiometric device which is simple in construction and with the elements thereof performing dual functions in the construction and functioning of the apparatus.

Another object of the present invention is to provide a new and improved potentiometric device which has a potentiometer element in the form of a ring, with that ring being rigidly fastened to a base member by a clamping element which has one surface thereof acting as a slip ring in the electrical operation of the device.

Still another object in the present invention is to provide a new and improved potentiometric device which has a plurality of potentiometer circuits built into a unitary structure utilizing a minimum of parts and associated to occupy a minimum of space.

These and other objects of the present invention will be obvious upon considering the following specification and drawings of which:

.Figure 1 shows a plan view of a portion of the device with a cover thereof removed;

Figure 2 shows a cross-section of Figure 1 taken along the line 2-2 with the rotating member of the device removed;

Figure 3 shows a plan view of the base member of the device with electrical terminals projecting therefrom; and

Figure 4 shows an enlarged perspective view of a portion of the device showing the relative positions of the electrical components of the device.

In considering the present invention, referring to Figure 1, there is provided a base member it! which is constructed of any suitable insulating type of material. This base member has a circular opening located in the center thereof. Centered around this circular opening is a potentiometer ring H on which there has been wound a suitable resistance wire. This potentiometer ring is centered about the center hole in the base member by a plurality of centering pins l 2 which are actually projections of the base member 10 projecting into holes in the potentiometer ring I I. The potentiometer ring [I is broken down into a plurality of sectors which have been indicated as HA, HE, and HC', the dividing point between the various sectors being indicated by the centering pins l2. In the particular showing of the device, the resistance wire has been wound on the potentiometer ring in the three sectors HA, II B, and HG though it will be obvious that additional sectors could be provided.

Directly associated with the potentiometer ring I I is a clamping ring 13, shown in cross-sectional detail in Figure 2. In Figure 2 it will be noted that the clamping ring is recessed on the outer edge so that the ring overlaps a portion of the potentiometer ring H. The clamping ring I3 is also recessed on its inner portion and on the side opposite the recession which fits over the potentiometer ring II. The recession on the inner portion of the clamping ring is also divided up into a plurality of sectors corresponding to the number of sectors on the potentiometer ring ll. Fitting over this inner recessed portion are a plurality of clamping members MA, MB, and HC and these clamping members each have a flat arcuate surface which parallels the arcuate surface of the potentiometer ring through an angular distance which corresponds to the angular distance of the sector of the potentiometer ring associated therewith. This clamping member projects at right angles from the surface of the clamping ring through the hole in the base member ID, as shown in Figure 2, and then at right angles along the opposite side of the base member If] to a point where the end thereof projects beyond the base member so that an electrical connection can be made thereto, as shown in Figures 1 and 3.

The clamping members MA, MB, and [4C are all recessed in the sides of the center hole the base member and also on the side opposite the potentiometer ring in the base member Iii. Each of the clamping members MA, MB, and MC have an enlarged portion lA, I53, and lEiC respectively located on the side of the base opposite the location of the potentiometer ring, as shown in Figure 3. This enlarged portion has a hole centered therein and the hole is in alignment with a further hole located in the base lb] beneath each of the members. While the clamping members I l are somewhat resilient and will rigidly fasten the clamping ring and potentiometer ring to the base member it), it is desired that these clamping members be further locked into position. This is accomplished by an end plate I5, shown in Figure 2. The end plate l-i has a plurality of projections which are adapted to be in line with the holes of the clamping members MA, MB, and MC. A cross-section of one of these projections is shown at I"! in Figure 2. The outside diameter of this projection is equal to the inside diameter of the hole in the enlargement l5 of the clamping members l4.

Centered in the hole of the base member It is a rotatable member also of suitable insulating material. This rotatable element has a pair of shoulders reset therein at 2! and 22 that are adapted to engage a projection 23 which is a part of the base member Iii located in the center hole. The projection 23, cooperating with the shoulders 2! and 22, limits the angular rotation of the rotatable member 29 so that this rotation will correspond to the angular distance of the sectors of the resistance wire wound upon the potentiometer ring H. The rotatable member 2a is carried by a shaft 24 and is fastened thereto by a nut 25, or other suitable means, all shown in Figure 1.

Carried by the rotatable member 29 area plurality of wiper arms 28 which, in Figure 1 have been indicated as 28A, 28B, and 280. Each of these wiper arms is directly associated with the potentiometer ring sector IlA, HB, and HC respectively, as well as the slip ring portions of the clamping members MA, 1 313, and MC. Each of these wiper arms carry two sets of contact members 29 which resiliently engage the resistance wire on the potentiometer ring H and the slip ring portion of the clamping member M. This is shown in perspective view in Figure 4. The contact members carried by the wiper arms may be either separate spring members fastened to the wiper arm or may be fabricated as a part of the wiper arm itself, as shown in Figure l.

Located beneath the potentiometer ring and recessed in the base member is are a plurality of further contact members 36. These contact members may be located in any desired position beneath the potentiometer ring although they are shown located at the end portions of each of the sectors of the resistance wire wound upon the potentiometer ring l i. This further contact member 38 is perspectively shown in Figure 4. It may be seen that this member comprises an elongated metal strip having an enlarged circular end with a portion thereof sprung outwardly to form a projection 3|. This projection, when the potentiometer ring is in position, is adapted to resiliently engage the potentiometer ring and make electrical contact therewith. When the potentiometer ring is in position, the contact member 30 is retained thereby in position in the base member ID.

Forming a cover for the device is a cylindrical member 34 constructed of insulative material. This circular member fits snugly over the raised portion 35 of the base member to upon which rests the potentiometer ring, shown in Figure 2. This member has a plurality of holes therein which are brought into alignment with the holes which are in the base member 89, the end plate l6 and the clalnping members l i. Extending through this hole is a screw 35, shown in Figure 2. The screw 36 may be used to fasten the entire assembly to a panel or other device, not shown. A cover plate 3'5 slips over the end of the member 34 and this cover plate is held in position by a plurality of screws 38.

It will be seen from the above description that the apparatus that is shown upon the drawing includes three potentiometer circuits with the sectors HA, HB, and I [C forming the resistance wire over the potentiometer circuit and with contacts 36 forming the fixed contacts on either end of the sectors HA, HE, and HC. It will be further seen that when the rotatable member 20 is moved the wiper arms 28A, 28B, and 280 are moved across their respective sectors IIA, HB, and HC so that an electrical circuit is completed from the resistance wire on the various sectors through the wiper arms to the clamping members MA, MB, and MC respectively.

From the foregoing it can be seen there has been provided a simple potentiometric device which is readily applicable for use where a plurality of potentiometric functions are required from a single moving element. Further, the device has a minimum of parts which are easily fabricated and assembled with many of the parts performing dual functions in the device. It will be obvious to those skilled in the art that many modifications can be made within the scope of the invention and therefore intend to be limited solely by the scope of the amended claims in which I claim:

1. A potentiometric device comprising, in combination, a base member composed of insulating material, a potentiometer ring of insulating material having a resistance wire thereon, a rigid circular clamping ring of insulating material adapted to overlap a portion of said potentiometer ring, a metallic member rigidly fastening said clamping ring to said base member so that said potentiometer ring is retained rigidly on said base, a wiper arm having contact members for engaging said potentiometer ring and said metallic member, said metallic member forming a slip ring through which an electrical circuit can be completed, and a rotating member carrying said wiper arm so that said wiper can be variably adjusted over said potentiometer ring and said metallic member.

2. A potentiometric device comprising, in combination, a base member composed of insulating material, a potentiometer ring of insulating material having a resistance wire supported thereon, a rigid circular clamping ring of insulating materia1 overlapping a portion of said potentiometer ring, a metallic member having an arcuate portion on one end thereof overlapping said clamping ring out of engagement with said resistance wire and fastening both said rings rigidly to said. base member, a wiper arm having a pair of contacts engaging said resistance wire and said arcuate portion of said member, a rotating member carrying said wiper arm so that said wiper can be variably adjusted over said potentiometer ring and said metallic member, and a plurality of fixed contact members recessed in said base member engaging said resistance wire at predetermined points.

3. A potentiometer device comprising, in com.-

bination, a base member composed of insulating material, a potentiometer ring of insulating material having a resistance wire supported thereon, a circular clamping ring overlapping a portion of said potentiometer ring, a metallic member having an arcuate portion on one end thereof overlapping said clamping ring out of engagement with said resistance wire and fastening both said rings rigidly to said base member, a wiper arm having a pair of contacts engaging said resistance wire and said arcuate portion of said member, a rotating member carrying said wiper arm so that said wiper can be variably adjusted over said potentiometer ring and said metallic member, and a plurality of fixed contact members recessed in said base member engaging said resistance wire at predetermined points, said contact members each having a portion thereof projecting from the main body of the member to resiliently engage said resistance Wire.

4. A potentiometric device comprising, in combination, a base member of insulating material having a center hole therein, a potentiometer ring having a resistance Wire thereon, said ring being centered about the hole in said base member, a rigid circular clamping ring of insulating material having an inside diameter equal to the diameter of said hole and said outside diameter slightly greater than the inside diameter of said potentiometer ring, said clamping ring being recessed on its outer portion to overlap said potentiometer ring and recessed on its inner portion in the opposite direction, and a metallic clamping member having an arcuate portion fitting into the recession on said clamping ring on the inner portion and extending laterally through the hole in said base and then at right angles to project beyond the edge of said base to form a terminal for making an electrical connection, said clamping ring and member fastening said potentiometer in a fixed position on said base member.

5. A potentiometric device comprising in combination, a base member of insulating material having a center hole therein, a potentiometer ring having a resistance wire thereon, said ring being centered about the hole in said base, a circular clamping ring having an inside diameter equal to the diameter of said hole and an outside diameter slightly greater than the inside diameter of said potentiometer ring, said clamping ring being recessed on its outer portion to overlap said potentiometer ring and recessed on its inner portion in the opposite direction, a metallic clamping member having an arcuate portion fitting into the inner recessed portion of said ring and extending laterally through the hole in said base and then at right angles to project beyond the edge of said base to form a terminal for making an electrical connection, said clamping ring and member fastening said potentiometer ring in a fixed position on said base member, and a plurality of electrical contact members recessed in said base member directly adjacent to said potentiometer ring and resiliently engaging said resistance Wire.

6. A potentiometric device comprising, in combination, a base member of insulating material having a center hole therein, a potentiometer ring having a resistance wire thereon, said ring being centered about the hole in said base, a circular clamping ring having an inside diameter equal to the diameter of said. hole and an outside diameter slightly greater than the inside diameter of said potentiometer ring, said clamping ring being recessed on its outer portion to overlap said potentiometer ring and recessed on its inner portion in the opposite direction, a metallic clamping member having an arcuate portion fitting into the inner recessed portion of said ring and extending laterally through the hole in said base and then at right angles to project beyond the edge of said. base to form a terminal for making an electrical connection, said clamping ring and member fastening said'potentiometer ring in a fixed position on said base member, a plurality of electrical contact members recessed in said base member directly adjacent said potentiometer ring and resiliently engaging said resistance wire, and a rotating member adapted to be positioned in the hole in said base member, said rotating member carrying a plurality of wiper arms which have contacts resiliently engaging said resistance wire and the arcuate portion of said clamping member.

'7. In a potentiometric device of the class described, the combination comprising, a base member comprising a ring of insulating material, a potentiometer ring supported on one side of said ring, a rigid clamping ring of insulating material adapted to overlap a portion of said potentiometer ring, a metallic member overlapping said clamping ring, said member extending through the center portion of said base member and laterally along the edge of said member opposite said potentiometer ring, said lateral extension of said member having a hole therein, said base member having a hole which is in alignment with said hole of said metallic member, and a cover member adapted to be fastened to said. base member on the side opposite said potentiometer ring having a projection fitting into the hole in said metallic member and said base member to rigidly fasten said metallic member to said base member.

8. In a potentiometric device of the class described, the combination comprising, a base member comprising a ring of insulating material, a potentiometer ring supported on one side of said ring, a rigid clamping ring of insulating material adapted to overlap a portion of said potentioineter ring, a metallic member overlapping said clamping ring, said member extending through the center portion of said. base member and laterally along the edge of said member opposite said potentiometer ring, said metallic member being recessed in said base member Where it is adjacent thereto and with said lateral extension of said member having a hole therein, said base member having a hole which is in alignment with said hole of said metallic member, and a cover member adapted to be fastened to said base member on the side opposite said potentiometer ring having a projection fitting into the hole in said metallic member and said base member to rigidly fasten said metallic member to said base member.

9. A po-tentiometric device comprising, in combination, a base member composed of insulating material, a potentiometer ring of insulating material having a resistance wire thereon, a rigid circular clamping ring of insulating material.

adapted to overlap a portion of said potentiometer ring, a plurality of metallic members having arcuate portions on one end thereof overlapping said clamping ring, said members extending through the center portion of said base member and laterally along the edge of said base member opposite said potentiometer ring with the lateral extension of each of said members having a hole therein, said base member having a plurality of holes, each of said holes in said base being in alignment with corresponding holes in said metallic members, said members being located in spaced relation to the other metallic members about the circumference of said clamping ring, and with said clamping ring rigidly fastening said potentiometer ring to said base member, and a rotating member carrying a plurality of Wiper arms which are adapted to engage said metallic members and said resistance wire.

10. A potentiometric device comprising, in combination, a base member composed of insulating material, a potentiometer ring of insulating material having a resistance wire thereon broken down into a plurality of sectors, a rigid clamping ring of insulating material overplapping a portion of said potentiometer ring, a plurality of metallic members having arcuate portions on one end thereof overlapping said clamping ring and aligned with each or" said sectors of said resistance Wire, said members being located in spaced relation about the circumference of said clamping ring and with said clamping ring rigidly fastening said potentiometer ring to said base member, said members extending through the center portion of said base member and laterally along the edge of said base member opposite said potentiometer ring with the lateral extension of each of said members having a hole therein.

8 said base member having a plurality of holes in alignment with the holes in said metallic members, a plurality of contact members mounted beneath. said potentiometer ring with each of said members resiliently engaging an end of each of said sectors of said resistance wire, a rotatable member mountable within said base member and having an angular movement corresponding to the arcuate length of each of said members, and a plurality of wiper arms having contact members engaging the respective sectors of said resistance Wire and said arcuate surfaces of said metallic members, said first mentioned contact members and said metallic members forming electrical terminals for a plurality of separate potentiometer circuits.

THEODORE J. WILSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 714,411 Steinmetz Nov. 25, 1902: 1,461,634 Stoekle July 10, 1923 2,021,487 McDonell et al Nov. 19, 1935 2,480,995 Armtage Sept. 6, 1949 

